Dowels – 9mm drill bit for dowel spawn. Lip and spur drill to drill accurate hole for the dowels. Needs to be used slowly or it will drill a deeper hole than needed – the hole should be no deeper than 1.5 times the length of dowel. You could use a 8mm HSS but they tend to wander in the hole and are not recommended. The dowels are 8mm but swell with the mushroom mycelium and moisture so a 9mm hole is ideal.
Sawdust Spawn – 12mm drill. The drill bit provided a perfect hole for the sawdust spawn plugs made by the inoculator. High speed, use with an electric drill or grinder.